====== Deploy SpringBoot 2 on Weblogic 12c ======
Deploying code on old container is a headache. Here is how I solve it. This example is based on SpringBoot 2.3.1.RELEASE, but should work on other 2.x version.
  - We need to have the following xml config in those files.
  - **!!!**The MS SQL driver ''sqljdbc42.jar'' would no longer work with new Hibernate 5, so you need to update to at least version 6.3.2 (''6.4.0.jre8 recommended'') on your WebLogic server**!!!**.

===== pom.xml =====

<code>
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.3.1.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.example</groupId>
    <artifactId>demo</artifactId>
    <version>SNAPSHOT</version>
    <packaging>war</packaging>
    <name>demo</name>
    <description>Demo project for Spring Boot</description>

    <properties>
        <java.version>1.8</java.version>
    </properties>
    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter</artifactId>
            <exclusions>
                <exclusion>
                    <groupId>org.springframework.boot</groupId>
                    <artifactId>spring-boot-starter-logging</artifactId>
                </exclusion>
                <exclusion>
                    <artifactId>logback-classic</artifactId>
                    <groupId>ch.qos.logback</groupId>
                </exclusion>
                <exclusion>
                    <artifactId>log4j-over-slf4j</artifactId>
                    <groupId>org.slf4j</groupId>
                </exclusion>
            </exclusions>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>


        <dependency>
            <groupId>io.jsonwebtoken</groupId>
            <artifactId>jjwt</artifactId>
            <version>0.9.1</version>
        </dependency>

        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <optional>true</optional>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-jdbc</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-jpa</artifactId>
        </dependency>

        <dependency>
            <groupId>com.microsoft.sqlserver</groupId>
            <artifactId>mssql-jdbc</artifactId>
            <version>6.4.0.jre8</version>
            <scope>runtime</scope>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-tomcat</artifactId>
            <scope>provided</scope>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
            <exclusions>
                <exclusion>
                    <groupId>org.junit.vintage</groupId>
                    <artifactId>junit-vintage-engine</artifactId>
                </exclusion>
            </exclusions>
        </dependency>

        <dependency>
            <groupId>org.slf4j</groupId>
            <artifactId>slf4j-log4j12</artifactId>
            <version>1.7.30</version>
        </dependency>

    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>

</project>

</code>

===== log4j.xml =====
This file located at ./src/main/resources/log4j.xml. You might un-comment the logger in this file if needed.
<code>
<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE log4j:configuration SYSTEM "log4j.dtd">

<log4j:configuration debug="true" xmlns:log4j="http://jakarta.apache.org/log4j/">

    <appender name="Console"
              class="org.apache.log4j.ConsoleAppender">
        <layout class="org.apache.log4j.PatternLayout">
            <!-- l, L, M - is extremely slow. It's use should be avoided unless execution
                speed is not an issue. -->
            <param name="ConversionPattern"
                   value="%p: %d{dd.MM.yyyy HH:mm:ss.SSS} %l %n    %m%n"/>
        </layout>
    </appender>

    <appender name="File"
              class="org.apache.log4j.DailyRollingFileAppender">
        <param name="Encoding" value="UTF-8"/>
        <param name="File" value="logs/trace.log"/>
        <param name="Append" value="true"/>
        <layout class="org.apache.log4j.PatternLayout">
            <!-- l, L, M - is extremely slow. It's use should be avoided unless execution
                speed is not an issue. -->
            <param name="ConversionPattern"
                   value="%p: %d{dd.MM.yyyy HH:mm:ss.SSS} %l %n    %m%n"/>
        </layout>
    </appender>

<!--    &lt;!&ndash; Application Loggers &ndash;&gt;-->
<!--    <logger name="com.journaldev.spring">-->
<!--        <level value="info"/>-->
<!--    </logger>-->

<!--    &lt;!&ndash; 3rdparty Loggers &ndash;&gt;-->
<!--    <logger name="org.springframework.core">-->
<!--        <level value="info"/>-->
<!--    </logger>-->

<!--    <logger name="org.hibernate">-->
<!--        <level value="info"/>-->
<!--    </logger>-->

<!--    <logger name="org.springframework.beans">-->
<!--        <level value="info"/>-->
<!--    </logger>-->

<!--    <logger name="org.springframework.context">-->
<!--        <level value="info"/>-->
<!--    </logger>-->

<!--    <logger name="org.springframework.web">-->
<!--        <level value="info"/>-->
<!--    </logger>-->

    <!-- The root category is used for all loggers unless a more specific logger
        matches. If none of the loggers are assigned a level, then all loggers inherit
        the level of the root logger which is set to DEBUG by default -->
    <root>
        <level value="warn"/>
        <appender-ref ref="Console"/>
        <!-- <appender-ref ref="File" /> -->
    </root>

</log4j:configuration>
</code>

===== weblogic.xml =====
This file located at /src/main/webapp/WEB-INF/weblogic.xml.

<wls:context-root>demo</wls:context-root> is the path of the URI of your application, you might want to change it to something else.

<code>
<?xml version="1.0" encoding="UTF-8"?>
<wls:weblogic-web-app
        xmlns:wls="http://xmlns.oracle.com/weblogic/weblogic-web-app"
        xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
        xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd http://xmlns.oracle.com/weblogic/weblogic-web-app http://xmlns.oracle.com/weblogic/weblogic-web-app/1.9/weblogic-web-app.xsd">

    <wls:context-root>demo</wls:context-root>

    <wls:weblogic-version>12.2.1.2</wls:weblogic-version>
    <wls:container-descriptor>
        <wls:prefer-application-packages>
            <wls:package-name>org.slf4j.*</wls:package-name>
            <wls:package-name>org.apache.commons.*</wls:package-name>
            <wls:package-name>org.springframework.*</wls:package-name>
            <wls:package-name>org.hibernate.annotations.common.*</wls:package-name>
            <wls:package-name>com.fasterxml.*</wls:package-name>
        </wls:prefer-application-packages>

        <wls:prefer-application-resources>
            <wls:resource-name>org/slf4j/impl/StaticLoggerBinder.class</wls:resource-name>
        </wls:prefer-application-resources>

    </wls:container-descriptor>
</wls:weblogic-web-app>
</code>